Cerebral pressure-flow relationship in lowlanders and natives at high altitude

Jonathan D. Smirl, Samuel J.E. Lucas, Nia C.S. Lewis, Gregory R. Dumanior, Kurt J. Smith, Akke Bakker, Aperna S. Basnyat, Philip N. Ainslie

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

    20 Dyfyniadau (Scopus)


    We investigated if dynamic cerebral pressure-flow relationships in lowlanders are altered at high altitude (HA), differ in HA natives and after return to sea level (SL). Lowlanders were tested at SL (n=16), arrival to 5,050 m, after 2-week acclimatization (with and without end-tidal PO 2 normalization), and upon SL return. High-altitude natives (n=16) were tested at 5,050 m. Testing sessions involved resting spontaneous and driven (squat-stand maneuvers at very low (VLF, 0.05 Hz) and low (LF, 0.10 Hz) frequencies) measures to maximize blood pressure (BP) variability and improve assessment of the pressure-flow relationship using transfer function analysis (TFA). Blood flow velocity was assessed in the middle (MCAv) and posterior (PCAv) cerebral arteries. Spontaneous VLF and LF phases were reduced and coherence was elevated with acclimatization to HA (P<0.05), indicating impaired pressure-flow coupling. However, when BP was driven, both the frequency- and time-domain metrics were unaltered and comparable with HA natives. Acute mountain sickness was unrelated to TFA metrics. In conclusion, the driven cerebral pressure-flow relationship (in both frequency and time domains) is unaltered at 5,050 m in lowlanders and HA natives. Our findings indicate that spontaneous changes in TFA metrics do not necessarily reflect physiologically important alterations in the capacity of the brain to regulate BP.

    Iaith wreiddiolSaesneg
    Tudalennau (o-i)248-257
    Nifer y tudalennau10
    CyfnodolynJournal of Cerebral Blood Flow and Metabolism
    Rhif cyhoeddi2
    Dynodwyr Gwrthrych Digidol (DOIs)
    StatwsCyhoeddwyd - 1 Chwef 2014

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